Add debug output

This should help us debug cases where users which should have been added
to the database can not be found.

refs: #536

internal/brokers/manager.go

@@ -163,6 +163,8 @@ func (m *Manager) NewSession(brokerID, username, lang, mode string) (sessionID s
 		return "", "", err
 	}
 
+	log.Debug(context.Background(), fmt.Sprintf("%s: New session for %q", sessionID, username))
+
 	m.transactionsToBrokerMu.Lock()
 	defer m.transactionsToBrokerMu.Unlock()
 	m.transactionsToBroker[sessionID] = broker

internal/services/pam/pam.go

@@ -256,6 +256,8 @@ func (s Service) IsAuthenticated(ctx context.Context, req *authd.IARequest) (res
 		data = ""
 	}
 
+	log.Debug(ctx, fmt.Sprintf("%s: Authentication result: %s", sessionID, access))
+
 	return &authd.IAResponse{
 		Access: access,
 		Msg:    data,

internal/users/cache/update.go

@@ -1,6 +1,7 @@
 package cache
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -9,6 +10,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/ubuntu/authd/internal/log"
 	"go.etcd.io/bbolt"
 )
 
@@ -75,6 +77,7 @@ func updateUser(buckets map[string]bucketWithName, userContent userDB) error {
 	}
 
 	// Update user buckets
+	log.Debug(context.Background(), fmt.Sprintf("Updating entry of user %q (UID: %d)", userContent.Name, userContent.UID))
 	updateBucket(buckets[userByIDBucketName], userContent.UID, userContent)
 	updateBucket(buckets[userByNameBucketName], userContent.Name, userContent)